I am teaching a class of MBA students in Nanjing in China. They are very disciplined, polite and well-experienced. But like many other Chinese students, they listen to the teacher, take notes and speak only when called upon in class. The classroom is quiet, too quiet for a Business English class. Sometimes it's hard to tell if they understand the topic. (I believe that students won’t learn English unless they keep on listening and talking.)

I wonder if there are some effective yet simple activities to arouse their interests and turn them to be good participants.

I have two thoughts. First, why don't you explain to them exactly why you would like them to be more vocal in class and let them know that it is not rude to talk in this kind of lesson.

Second, why not take a task-based approach; it's really suitable for BE. For example, you could have a mock meeting every week where they have to discuss items on an agenda. For example, ask them to imagine there are major security issues in the office where they work and ask them to prepare ways to improve the security before coming to the meeting ... you get the idea.

Something that I find is really useful is to get the students to present a chapter of the book at the beginning of each class.
So for example, in my second class I tell them they are each going to present a chapter to the class and I give them one week to choose which chapter they want to present.
Usually I get very few replies so I assign chapters to them and some of them start to tell me they don't know what to say aout the chapter. So I give them a few hints that are just generally related to the chapter.

I find they give the presentation and introduce a lot of new vocab to the class. I then always emphasize that they should ask the speaker some questions. That way they need to listen to the speech and can feel guilty if they didn't . I do get some questions, but in general it leads to a more discursive atmosphere.